Energy efficient log cabin construction workshop

[Music] we scribed all that and we're getting ready to notch they're chiseling out the notches so we don't over cut with a chainsaw this is either called scribe fit or full scribe fit sometimes Scandinavian cope or Swedish cope but the idea is that all of the log surfaces have been hand fitted to each other so there are no gaps and it's all wood on wood joinery [Music] [Applause] [Music] [Applause] you guys pin this together with something to on any kind of Olli log screws or anything like that not only log screws because we have to allow for shrinkage of each individual log and the settling of the entire log wall gets shorter these are green logs so they're gonna each log will shrink in diameter and the shrinkage is usually about four percent radially in the log okay we also got about 1% compression of the logs from the weight of the roof and the logs themselves there's an hour up to 5% settling and then we allow 1% extra for a safety factor so we allow for 6% settling in these things you have to have an air in a vapor seal on the inside and out and if you do if you if the house is tight then it will be much easier to keep warm as time goes on this gap closes up that log comes down and touches that log the full length and that gasket compresses and that the fact that it's compressed is what keeps the air vapor and exterior air and water from coming in there are a lot of log homes in Alaska that were built in the 80s that only had loose fibreglass stuff in here and that that is not an air barrier now fiberglass is used for air filters air can pass through fiberglass and of course the other problem is is that if there's any gaps here then you have the warm humid air inside the house in the winter time getting into the dewpoint and freezing and frost plugs build up in that gap in that fabric less so you have to have a way to seal air from getting into or out of this groove cavity well and we all know that I mean that's the way that frame houses are built you have to have a vapor barrier I have to have a way to keep that insulation dry the more quickly the logs dry the more likely they are to to check and twist it takes about four or five years for the moisture content of logs to come to equilibrium with the local climate called EMC equilibrium moisture content four or five years after the roof is on windows and doors are and you're living in at four or five years and then that's it it'll shrink and settle during that period but not after and it I have seen homes that were heated especially if they're heated with something like wood and those logs that are close to the wood heat source dry out too quickly and so especially in a climate like this which is super cold continental climate in the wintertime you got a humidifier you got to humidify your house in the wintertime but one thing is more comfortable if is for another thing it's going to slow down that extreme drying stress that you have from sources like wood stove all logs develop a major check and then lots of small minor checks and by cutting a single chainsaw cut in the top of each log we're able to help the log decide where it's going to crack and it's good the best place is on top of the log it looks like a tiny check on the surface but it's already in here or inch and a half inch and three quarters so you measure that distance from the bottom of that check to here to the center of the log the kerf would have to be closer to the center than the bottom of that check is to the center and then you can have an influence on it but if you haven't gotten to it by then you're gonna have to go deeper and deeper there are some builders who who kerf almost to the pith the heart of each log and so they got a much better chance of causing the check to happen on top instead of somewhere else an op facing check on the outside surface is gonna catch water a check that spirals into the into the lawn Grove area is going to leak air even if there is a gasket and insulation inside so it's best if each log cracks on top where it's totally sealed Windham and weather can't get to it it's inside that gasket is insulated cavity and the homeowners like it too because then they don't see so many checks in their house all pines and spruces start out their lives with a bit of left-hand spiral twist to their grain so it's the nature of juvenile wood in in gymnosperms to start out left so if on the surface of the log you now see a straight grain or a right-hand spiral you know that it has changed over time and it does it changes just you know half a degree each year for a hundred years there you go you get a spiral green but if the log is still left-hand spiral on its surface now and the surface the log is ninety or a hundred and ten years old then you know that log is left-hand spiral grain all the way from the core to the outside and there's no way to balance those drying stresses they're all lined up in the same way left-hand so if it's left hand on the outside we've tried to put that log low down in the building where there's lots of weight on it and I can't twist so much the right hand trees and the straight grain trees were free to use them wherever we like how do you judge right-hand spiral well you know it's like for me it's like you know asking a better how does he judge a curve ball you know I can just look at it and see them but here's the trick you put your right hand on the log and if the if the check goes the direction of your fingers it's right hand if the check goes the other direction the direction of your thumb and it's left hand so this put my right hand on the log this check is more or less going the direction of my fingers so it's right hand [Music]

Channel: ColdClimateHousing

Views: 171,650

Keywords: CCHRC, log cabin, energy efficient, Robert Chambers

Id: wcKTtc8m02Y

Length: 7min 39sec (459 seconds)

Published: Tue May 28 2013